1. Field of the Invention
The present invention relates to an operation device which bend-operates, by motor driving, a bending section that is provided at a distal end side of an insertion section of an endoscope, and to a bending operation device of the endoscope.
2. Description of the Related Art
In general, a flexible endoscope, in which an insertion section that is to be inserted into the body has flexibility, has widely been used. The insertion section of the flexible endoscope includes an elongated flexible tube section, a bendable bending section which is continuously provided at a distal end of the flexible tube section, and a distal-end rigid section which is provided at a foremost end portion of the insertion section.
An operation section is provided at a proximal end portion of the insertion section. The operation section is provided with bending operation input means such as a bending operation lever. A bending amount of the bending section is instructed and input by operating the bending operation input means, such as a bending operation lever of the operation section. At this time, the bending amount of the bending section is set by, e.g. a bending position and a bending speed of the bending section. Further, on the basis of the bending amount that is instructed and input from the bending operation input means, a bending operation wire is pulled and operated and the bending section is bend-operated.
Jpn. Pat. Appln. KOKAI Publication No. 2004-321612 (patent document 1) discloses a motor-driven bending endoscope as bend-driving means of a bending section. In the motor-driven bending endoscope, a driving motor is built in an operation section. The motor is rotated and controlled, and a bending operation wire is pulled and operated by the driving force of the motor. Thereby, the bending section is bend-operated by motor driving.
In this case, the operation section is provided with a joystick as bending operation input means. The joystick includes an operation shaft which is vertically erected on a base. The operation shaft is pivotally supported such that a proximal portion of the operation shaft is pivotable about a pivotal support point. Normally, the operation shaft is urged in a state in which the operation shaft is held in a neutral position where the operation shaft is vertically erected on the base. At this time, the bending section is held in a non-bent shape in which the bending section extends straight.
In addition, the maximum inclination angle of the operation shaft of the joystick, at a time when the operation shaft is inclined in an arbitrary direction from the neutral position (inclination angle: 0°) about the pivotal support point, is set at, e.g. about 30°. The maximum bend angle of the bending section, which bends in accordance with the inclining operation of the operation shaft of the joystick, is set at, e.g. about 180° or 160°. At this time, the inclining operation angle of the operation shaft of the joystick is set to be proportional to the bend angle of the bending section. Accordingly, the bend angle of the bending section is set to be greater, compared to the inclining operation angle of the operation shaft of the joystick. For example, when the inclination angle of the operation shaft of the joystick is 1°, the bending section is bend-operated at a bend angle of about 6°.
Jpn. Pat. Appln. KOKAI Publication No. 2003-230535 (patent document 2) discloses a motor-driven bending endoscope having a structure that is different from the structure of patent document 1. In this case, a bag in which a liquid having viscosity is sealed is provided, as a resistor to the inclining operation of an operation shaft of a joystick functioning as bending operation input means, so as to cover a part of the operation shaft of the joystick.
When the joystick is operated, the bag is deformed in accordance with the inclining operation of the operation shaft. At this time, an operational resistance to the joystick is caused by operating the operation shaft against the viscous force of the liquid having viscosity, which is sealed in the bag. By this structure, the operator's unintended bending operation of the bending section can be prevented.
It is also disclosed that a first bag, in which a liquid with low viscosity is sealed, is provided on the operation shaft side of the joystick, and a second bag, in which a liquid with high viscosity is sealed, is provided outside the first bag. In this case, at the time of operating the joystick, if the operation shaft of the joystick is slightly operated, as in a case of bend-operating the bending section at a small bend angle, the operational resistance decreases. In addition, it is described that if the operation shaft of the joystick is greatly operated, as in a case of bend-operating the bending section at a large bend angle, the operational resistance increases.
Jpn. Pat. Appln. KOKAI Publication No. 2003-135385 (patent document 3) discloses a structure wherein an operation shaft of a joystick is attached via a rubber boot which is watertightly provided on a casing of an operation section in which the joystick is assembled. In this case, an adjusted margin is provided in a recess portion for disposing the rubber boot, in which the rubber boot is disposed. Thus, by attaching the rubber boot in accordance with the neutral position of the joystick, the restoration of the operation shaft itself of the joystick to the neutral position is not influenced by non-uniformity of attachment of the rubber boot.